Friday's runoff presidential election in Iran is a contest between Tehran's mayor and a national political figure. The contest has come to underscore the gap between rich and poor in Iran.

The economic divide in Iran can be drawn like an equator across the capital, between the affluent of north Tehran, with its trendy shops and large homes, and the poor of South Tehran, where unemployment is rife and poverty commonplace.

At the polling place at the Hussein-e-Ershad mosque complex in north central Tehran, the crowd seems to be split between backers of former President Ali AKbar Hashemi Rafsanjani and Tehran Mayor Mahmood Ahmadinejad.

But go to the Nabi Mosque in South Tehran, and Rafsanjani supporters are far more scarce.

In the days leading to Friday's vote, the runoff contest brought into focus the gap between rich and poor, and the divide between the old establishment and a new generation of politicians.

Mr. Rafsanjani was the presumptive favorite in the first round of balloting, but did not get enough votes to win outright. Mr. Ahmadinejad, who was given virtually no chance, came in second among the seven candidates who were given official permission to run.

Ali Akbar Hashemi Rafsanjani casting his vote in Tehran

Mr. Rafsanjani, 70, has sought to portray himself as a moderate with governmental experience, who will boost investment and trade and is open to at least some political liberalization.

In north Tehran, Ali Mohammad Afshan says he did not vote in the first round, but he did in the runoff election because he likes Mr. Rafsanjani's experience and his support for democratic reforms.

Mr. Ahmadinejad, 49, is a conservative hardliner and former Revolutionary Guard, who ran a populist campaign promising to help the poor and battle unemployment. Joblessness is officially at 16 percent, but may well be much higher. He has promised subsidy payments to Iranian citizens.

Ardent reformists, many of whom come from north Tehran and university campuses, have said they are not keen on Mr. Rafsanjani, but would vote for him, because they fear Mr. Ahmadinejad would roll back what gains have been made in democratic reforms.

But in south Tehran, voters express concerns about jobs and their pocketbooks. Masood Taheri, a just graduated student of veterinary medicine, says Mr. Ahmadinejad is seen as the opposite of the well-off people of north Tehran.

"I think he is a great man. And I can refer to the differences between the rich and the poor in Iran that was the best reason for voting for Mr. Ahmadinejad,” he noted. “People who are very, very rich, they haven't seen any poor people. So, that's why they are choosing Mr. Hashemi Rafsanjani. But the other people who are living in the southern part of Tehran, I can say I'm sure, dead sure, that all of them will choose this man [Ahmadinejad]."

Results of the runoff election should be known sometime late Saturday.